Magnetic revolution counter



y www.A MAGNETIC REVOLUTION COUNTER.

APPLICATION FILED OCT. 8, 1920- Patentea June 13, 1922;

4 SHEETS-SHEET l'.

.N. GRAY.

MAGNETIC REVOLUTION COUNTER.

APPLICATION FILED OCT- B. 1.920.

'Patented June 13, 1922.

4 SHEETS-SHEET 2.

N.GRAY. MAGNETIC 4REVOLUTION COUNTER. APPLICATION HLED )CT. 8. 1920.

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l N. GRAY. l MAGNETIC REVOLUTION COUNTER. I v APPUCATION FILED OCT. 8,1920. 1,419,253. Patented June 13, 1922 4 SHEETS-SHEET 4.

TTMTHWTTHmi UNITED STAT-ss PATENT oFFICE.I

NEIL GRAY, 0F DAYTON, OHIO.

MAGNETIC REVOLUTION COUNTER.

.Application mea october e, 192e. serial No. 415,528.

T0 allwlwm tana-y concern: `Be it lrnown that l, Ninn GRAY, a citizen ofthe United States, residing at `McCook Field, Dayton, in the county ofMontgomery and State of Ohio, have invented certain new and usefulImprovements in Magnetic Revolution Counters, of `which the followinglis a specification.

My invention relates toa magnetic revolution counter, the broad objectin view being to provide an apparatus of the charac- `ter ieferred towhich will accurately count or register the revolutions oflany shaft,engine, motor, or machinery of any` kind where it is required to notethespeed ofthe shaft at different stages, vas for example when computingthe horse powerA of an engine of any kind, motors and propellers.

In calculating the horse power of engines and the thrust of propellers,for example, it is important to note the speed of rotation of the shaftat different times and under different operating conditions in order tolay yoff the horse power curves and compare the etlif ciency of`different engines under same conditions and different `types ofpropellers; y

The invention hereinafter particularly described `is especially valuablein places where it would be inconvenient to get access to the end of ashaft with the ordinary hand revolution indicator or counter. The Vim-`proved counter is adapted to bev attached to any engine, turbine `orshaft, the `indicating member' or unit ofthe instrument being rvplacedinany convenient position and atfany `desired. distance from theremainder of the device, as, forexample, on the engineers operating deckor in the captains cabin or the pilots house of a vessel, the apparatusembodying` circuit wires which may :be led* from yone 'part .of theapparatus to the other irrespective kof location'and distance. The

- apparatus forming the subject-matter of this invention has beenaccurately tested up to the speed of 8,00() R. l). M.; `it opera-tes bya positive movement for each revolution, differing therein from theordinary electric or friction drive tachometer or speed counter.

The apparatus comprises two main units consisting of a rotary polarityreversing switch and an indicating Vmechanism controlled by suolireversing switch.

Vith the above and other objects in view the inventionconsists in thenovel construcescapement mechanism tion, combination and arrangementherein `fully described, illustrated and claimed.

In the accompanying` drawings:

Figure l is a vertical longitudinal section of the rotarypolarityreversing switch;

Fig-ure 2 is a vertical cross ysection through y the same taken about inline with the cam;

Figure 3 is a plan view thereof withthe snap cover removed;

Figure 4 1s a front elevation or face view of the indicator Figure 5 isa vertical transverse section through the same showing the ,gearing ofthe Figure 6 is a fore and aft section through the indicator taken aboutin line with the arbor of the indicating hand or. pointer;

Figure 7 is a fragmentary vertical section on the line 77`of Figure 6;and

Figure 8 isa diagram of thecomplete apparatus showing the wiring-system.

rlhe rotary polarity-reversing switch will first be described. Saidswitch comprises a rotary shaft 1, which is preferably mounted inaiiti-frictionball bearings 2 adjacent .to the opposite ends thereof andsupported within a casing or housing 3, preferably yoil tight, for ya`purpose which will appear.

Associated with `the shaft 1 is also an end thrust bearing .4: held inplace within lan extension of thel housing 3 Vby means of a detachableend plate 5. f

At the end of the shaft ,1 opposite the bearing 4: there .is secured totheshaft 1, so as to rotate therewith,-y a friction head 6 capable of alimited ymovement longitudinally of the shaft 1 by means cfa `pinfor,key 7 and slot Q8, the head Gbeing lbacked .by Ya thrust springt) to=maintain,permanent frictional contact between the friction head 6 andthe end of a shaft, the speed of rotation of "which is to be registered;`The-.head 6 carries .aA face member 10 .of frictional material, suchasrubber or a composition of rubber, said friction face member beingshown as provided with a central frictional protuberance 11 for directcontact-with the shaft end.

The casing or housing 3` embodies -a supporting base 12 having aAdovetailed sliding engagement with a stationary base 13 as shown at 14.The base 12 is provided at opposite .ends thereof with eyes 15 in orderto enable an operating ,cable y(notshown)` to CII . of rotation of'which is to be noted.

Fast on the shaft 1 within the casing 3 is a generally cylindrical cam16 having circumferential grooves 17 in the outer peripheral facethereof, said grooves being laterally spaced from each other by mea-nsof an intervening web or annular rib 18. The groores Il? areinterconnected by cross over grooves or ways 19 extending in reverse andoblique directions. and in conjunction with the cam 16 I employ aswiveled or pivotally mounted shoe 20. The shoe 2O has a shank or stem21 which is journaled in a bearing opening in the free end of anopcrating arm 22 extending above the cam and connected by a key or pin23 to the lower end of an upright rock shaft 2d. The shaft 2t passesthrough an oil `tight bearing' 25 in the top wall or cap plate 25 of thehousing 3. Above the plate 25 and fastened to the rock shaft 211- bymeans of a key or equivalent thereof is an oscillatory contact or switcharm 26, having its free end forked as indicated at 27. Attached to theforked ends of the arm 26 are circuit contact pieces 28 facing inopposite directions, said contact pieces being insulated by means of ablock 29 of insulating material. The contacts 28 are electricallyconnected by a conductor 30 to a central binding post 31 extendingthrough and insulated from a supporting block 32. Arranged at oppositesides of the switch arm 26 are other contacts 33 which are insulatedfrom but carried by opposed arms 34- mounted upon a common pivot post 35which however enables the arms 34; to swing independently of each other.A contractile spring 34: connects the arms 34C to maintain one set ofcontacts in contactual relation to each other but I iermitting theopposite arm 341- to move independently. The contacts are connected byflexible conductors 36 to binding posts 37 at opposite sides of thebrufling post 31, above referred to, and supported by the saine block32. A snap coveror hood SS extends over the mechanism just abovedescribed and detachably applied to tbe plate 25 hereinabove referredto. Stogjis are provided to limit the inward movement of the arms 3dtoward each other.

The indicator, forming the other main unit of the apparatus, comprises acasing or framework 40 mounted upon a suitable supporting base 41 andcontaining a train of gears 42,43, 44, 4:5 and 45 similar to theordinary eseapement movement of a clock mechanism, 46 designating thewinding arbor of such clock mechanism, and 47 rep resenting' theescapement pawl or lever, the parts just referred to being clearly shownin VFigure 5. The arbor 4.8 of the escapement wheel extends through thefront of the casing andA has an indicating hand 49 fast thereon. Thehand 49 is adapted to sweep around a graduated dial 50, which isnormally stationary but which may be adjusted axially around the arbor1S by means of a suitable thumb piece or handle 5l. This enables 'thedial 50 to be moved until the zero mark thereon registers with thepointer or hand a9. rlhis renders it unnecessary to set the hand 49 instarting a new operation of the indicator, the dial 50 being adjusted orset in lieu thereof.

Referring particularly to Figures 6 and 7 itwill be observed that thearbor of the verge 4J carries a permanent bar magnet or armature 52, theopposite ends of which are alternately attracted and repelled by polaruized relay magnets suitably fast in casing 4- 0 and electricallyconnected with the rctary polarity reversing .switch hereinabovedescribed. The wiring connections are illustrated in the diagrammaticview, Figure 8, wherein it will be seen that the neutral. wire 54 of thebattery extends to one sido of the polarized relay 53, the opposite sideor magnet of said relay being connected by wire 55 with one pole of aquick action snap switch 56 which may be quickly manipulated by handwhen the counting is to begin. From the opposite side of the switch 56 awire 57 extends to the central binding post 31 of the reversing switch.Wires 58 extend from the opposite negative binding posts 37 of the re*versing switch to the positive and negative binding posts of thebattery.

The operation of the apparatus is as follows: The polarity reversingswitch is moved into position by any suitable means, such as the meansabove described. Such movement is continued until the frictional contactmember at the end of the rotary shaft 1 moves to driving contact withthe shaft, the revolutions of which are to be counted. As the shaft 1rotates, the direction ot How of the current is changed, causing themagnets of the relay to alternately attract and repel the armature,thereby causing' a rocking movement of the verge arbor and acorresponding rocking movement of the escapement pawl fl-7. As thistakes place, the hand 49 revolves with an intermittent movement entirelyaround the dial. ln actual use contact is first made with the shaft, thespeed of rotation of which is to be registered. The dial is then turnedso as to register Zero with the hand. The operator then quickly closesthe snap switch 56 at the moment that the second hand of his watchreaches the peint where the observationis to be made. The operator nownotes `pointer or hand i9 and when the second hand of his watch reachesthe point determined by him, the switch 5G is opened. Thus is determinedthe exact number ofk revolutions of the shaft per minute. Itmatters nothow far the indicator may be removed from the polarity reversing switchas the only connections between the switch and indicator` consist ofwires or electrical conductors which of course may be of any length.Furthermore, the polarity reversingy switch may be operated in anyposition or at any angle.`

I claim:

l. A magnetic revolution counter embodying an indicating member, anescapement mechanism to operate said member, an electric circuit, apolarity-rei'ersinp,v switch in said circuit, and a polarized relaybetween said switch and escapement mechanism, said switch comprising` arotary shaft, an oscilla` tory switch arm, -a cam on said shaft tooperate said arm, and circuit contacts in the path of said arm.

2. A magnetic revolution counter embodying an indicating member, anescapement mechanism to operate said member, an electric circuit, apolaritynreversing switch in said circuit, including a rotary shaftadapted to be driven by frictional contact, and a polarized relaybetween said switch and escapement mechanism. Y

3. A magnetic revolution counter embodying an indicating member, an`escapement mechanism to operate said member, an electric circuit, apclarity-reversing` switch in said circuit, and a polarized relaybetween said switch and escapement mechanism, said switch comprisingarotary shaft, a cam on said shaft, a rock shaft, an operating arm onsaid shaft oscillated by said cam, a switch aim on said rock shaft,andopposed circuit contacts in the path of said arm.

Li, A magnetic revolution counter embody` ing an indicating member, anesca-pement mechanism to operate said member, an electric circuit, apolarity-reversing switch in said circuit, and a polarized relay betweensaid switch and escapement mechanism, said switch comprising a rotaryshaft, a cam on said shaft, a rock shaft, an operating arm` on saidshaft oscillated by said cam, a switch arm on said rock shaft, andopposed yieldably sustained circuit contacts in the path of said arm. i

In testimony whereof I have atxed my signature. i i

NEIL GRAY.

